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Welding table thickness

Hey guys, I want to fab a welding table out of aluminum. The top will be 4'x4'. In your opinion, what would be a good thickness. I was thinking between 1/4 and 3/8ths. I don't want it to bend or flex. Thanks for any input, Ja.

Thanks for the reply Monte, the table will spend the majority of its time outside and will be moved into the shop when I need to work on a project. I don't have alot of shop room to keep it inside. Therefore, weight is an issue along with corrosion. Aluminum would be better than steel for my ap. I mig and tig both alum and steel, mostly small projects, ie under 100 lbs.

Aluminum outside will get nasty also. Will you need to have access all 4 sides of the table? If not, and you have wall space, attatch it to the wall with hinges. Flip up when you need it and down when you don't. I would still go with steel because it's cheaper, and you tack jigs etc to the table if need be. Even if the steel was outside, coat it and cover it and its will be fine. I wouldn't my welding table outside. It's unsitely and a piece of aluminum that big is inviting theft.

I assume you will have a steel base under it. Of course you know you will not weld the alum plate to it so you will need to bolt it. Depending on the bracing under the top, you might get by with 1/4" bit if allowed to get hot during welding it may not stay flat. Myself, I would like to have at least 1/2" top. Then you could have overhang for clamping and such. With only 1/4" top and overhang, it will be too easy to deform the overhang when loadindg something heavy on it and it hits the edge. So much depends on how you will use the table.

I had an aluminum welding table, don't use it anymore because as soon as you have something clamped on it that overhangs, it would flip. Just wasn't heavy enough. You would want it pretty thick because it flexed a lot too.

Aluminum would get trashed so fast with sharp, burr and slag covered pieces of steel. I would never build a welding table with less than 3/8 steel, and that would need good bracing built into it. I have 3/4 steel for my top. Just my opinions though. I understand you need to be able to move it. Any way you could just build a set of nice casters into a full steel table so it could still be moved? Steel would be fine outside if it got a nice coating everywhere but the top surface. Would just take a little maintaince to clean up the top when you need it.

Looking at your list of equipment there and it looks to me you have a pretty decent handle on what you need.
That said, I'm guessing your wallet will help you make this decision.
Simply imagine a heavy steel table and go from there.
Heavy duty legs and all that good stuff. It'll be expensive
There are many times I wish I had an aluminum top on my table for aluminum work.
If money isn't a problem, then you may wanna go with stainless instead.
Back on the aluminum I would say 1/4" would be ok as long as you didn't clamp anything much to it. Anything thicker would be better of course.
The advice about nothing heavy, no hard (sledgehammer) banging/wailing, or steel mig/stick welding just goes almost without saying.
I feel the alloy is as important as anything. Go with 6061 and it will be a ton stiffer than say like 3003 or even 5052. Use a heavy frame and barely tack or even tap and bolt the top down and it will stay flat.
I have a 10ft plate of 5/16ths unknown alloy and it's gonna be a table top for sure someday more than likely. I feel like it can't be beat for aluminum tubing projects like I do on boats.....YMMV.....HTH